blob: 3690360d7a798ec98f73e58bb83880fe01e99de3 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * hosts.c Copyright (C) 1992 Drew Eckhardt
3 * Copyright (C) 1993, 1994, 1995 Eric Youngdale
4 * Copyright (C) 2002-2003 Christoph Hellwig
5 *
6 * mid to lowlevel SCSI driver interface
7 * Initial versions: Drew Eckhardt
8 * Subsequent revisions: Eric Youngdale
9 *
10 * <drew@colorado.edu>
11 *
12 * Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli
13 * Added QLOGIC QLA1280 SCSI controller kernel host support.
14 * August 4, 1999 Fred Lewis, Intel DuPont
15 *
16 * Updated to reflect the new initialization scheme for the higher
17 * level of scsi drivers (sd/sr/st)
18 * September 17, 2000 Torben Mathiasen <tmm@image.dk>
19 *
20 * Restructured scsi_host lists and associated functions.
21 * September 04, 2002 Mike Anderson (andmike@us.ibm.com)
22 */
23
24#include <linux/module.h>
25#include <linux/blkdev.h>
26#include <linux/kernel.h>
Christoph Hellwigc5478de2005-09-06 14:04:26 +020027#include <linux/kthread.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070028#include <linux/string.h>
29#include <linux/mm.h>
30#include <linux/init.h>
31#include <linux/completion.h>
32#include <linux/transport_class.h>
Russell Kingd052d1b2005-10-29 19:07:23 +010033#include <linux/platform_device.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070034
35#include <scsi/scsi_device.h>
36#include <scsi/scsi_host.h>
37#include <scsi/scsi_transport.h>
38
39#include "scsi_priv.h"
40#include "scsi_logging.h"
41
42
43static int scsi_host_next_hn; /* host_no for next new host */
44
45
Tony Jonesee959b02008-02-22 00:13:36 +010046static void scsi_host_cls_release(struct device *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -070047{
Tony Jonesee959b02008-02-22 00:13:36 +010048 put_device(&class_to_shost(dev)->shost_gendev);
Linus Torvalds1da177e2005-04-16 15:20:36 -070049}
50
51static struct class shost_class = {
52 .name = "scsi_host",
Tony Jonesee959b02008-02-22 00:13:36 +010053 .dev_release = scsi_host_cls_release,
Linus Torvalds1da177e2005-04-16 15:20:36 -070054};
55
56/**
Rob Landleyeb448202007-11-03 13:30:39 -050057 * scsi_host_set_state - Take the given host through the host state model.
Mike Andersond3301872005-06-16 11:12:38 -070058 * @shost: scsi host to change the state of.
59 * @state: state to change to.
60 *
61 * Returns zero if unsuccessful or an error if the requested
62 * transition is illegal.
63 **/
64int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
65{
66 enum scsi_host_state oldstate = shost->shost_state;
67
68 if (state == oldstate)
69 return 0;
70
71 switch (state) {
72 case SHOST_CREATED:
73 /* There are no legal states that come back to
74 * created. This is the manually initialised start
75 * state */
76 goto illegal;
77
78 case SHOST_RUNNING:
79 switch (oldstate) {
80 case SHOST_CREATED:
81 case SHOST_RECOVERY:
82 break;
83 default:
84 goto illegal;
85 }
86 break;
87
88 case SHOST_RECOVERY:
89 switch (oldstate) {
90 case SHOST_RUNNING:
91 break;
92 default:
93 goto illegal;
94 }
95 break;
96
97 case SHOST_CANCEL:
98 switch (oldstate) {
99 case SHOST_CREATED:
100 case SHOST_RUNNING:
James Bottomley939647e2005-09-18 15:05:20 -0500101 case SHOST_CANCEL_RECOVERY:
Mike Andersond3301872005-06-16 11:12:38 -0700102 break;
103 default:
104 goto illegal;
105 }
106 break;
107
108 case SHOST_DEL:
109 switch (oldstate) {
110 case SHOST_CANCEL:
James Bottomley939647e2005-09-18 15:05:20 -0500111 case SHOST_DEL_RECOVERY:
Mike Andersond3301872005-06-16 11:12:38 -0700112 break;
113 default:
114 goto illegal;
115 }
116 break;
117
James Bottomley939647e2005-09-18 15:05:20 -0500118 case SHOST_CANCEL_RECOVERY:
119 switch (oldstate) {
120 case SHOST_CANCEL:
121 case SHOST_RECOVERY:
122 break;
123 default:
124 goto illegal;
125 }
126 break;
127
128 case SHOST_DEL_RECOVERY:
129 switch (oldstate) {
130 case SHOST_CANCEL_RECOVERY:
131 break;
132 default:
133 goto illegal;
134 }
135 break;
Mike Andersond3301872005-06-16 11:12:38 -0700136 }
137 shost->shost_state = state;
138 return 0;
139
140 illegal:
141 SCSI_LOG_ERROR_RECOVERY(1,
James Bottomley9ccfc752005-10-02 11:45:08 -0500142 shost_printk(KERN_ERR, shost,
143 "Illegal host state transition"
144 "%s->%s\n",
145 scsi_host_state_name(oldstate),
146 scsi_host_state_name(state)));
Mike Andersond3301872005-06-16 11:12:38 -0700147 return -EINVAL;
148}
149EXPORT_SYMBOL(scsi_host_set_state);
150
151/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152 * scsi_remove_host - remove a scsi host
153 * @shost: a pointer to a scsi host to remove
154 **/
155void scsi_remove_host(struct Scsi_Host *shost)
156{
James Bottomley939647e2005-09-18 15:05:20 -0500157 unsigned long flags;
Arjan van de Ven0b950672006-01-11 13:16:10 +0100158 mutex_lock(&shost->scan_mutex);
James Bottomley939647e2005-09-18 15:05:20 -0500159 spin_lock_irqsave(shost->host_lock, flags);
160 if (scsi_host_set_state(shost, SHOST_CANCEL))
161 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
162 spin_unlock_irqrestore(shost->host_lock, flags);
Arjan van de Ven0b950672006-01-11 13:16:10 +0100163 mutex_unlock(&shost->scan_mutex);
James Bottomley939647e2005-09-18 15:05:20 -0500164 return;
165 }
166 spin_unlock_irqrestore(shost->host_lock, flags);
Arjan van de Ven0b950672006-01-11 13:16:10 +0100167 mutex_unlock(&shost->scan_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168 scsi_forget_host(shost);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169 scsi_proc_host_rm(shost);
170
James Bottomley939647e2005-09-18 15:05:20 -0500171 spin_lock_irqsave(shost->host_lock, flags);
172 if (scsi_host_set_state(shost, SHOST_DEL))
173 BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
174 spin_unlock_irqrestore(shost->host_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175
176 transport_unregister_device(&shost->shost_gendev);
Tony Jonesee959b02008-02-22 00:13:36 +0100177 device_unregister(&shost->shost_dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178 device_del(&shost->shost_gendev);
James Bottomley9e705922005-10-02 12:59:49 -0500179 scsi_proc_hostdir_rm(shost->hostt);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180}
181EXPORT_SYMBOL(scsi_remove_host);
182
183/**
184 * scsi_add_host - add a scsi host
185 * @shost: scsi host pointer to add
186 * @dev: a struct device of type scsi class
187 *
188 * Return value:
189 * 0 on success / != 0 for error
190 **/
191int scsi_add_host(struct Scsi_Host *shost, struct device *dev)
192{
193 struct scsi_host_template *sht = shost->hostt;
194 int error = -EINVAL;
195
196 printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
197 sht->info ? sht->info(shost) : sht->name);
198
199 if (!shost->can_queue) {
200 printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
201 sht->name);
James Bottomley542bd132008-04-21 10:57:20 -0500202 goto fail;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203 }
204
James Bottomley542bd132008-04-21 10:57:20 -0500205 error = scsi_setup_command_freelist(shost);
206 if (error)
207 goto fail;
208
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209 if (!shost->shost_gendev.parent)
210 shost->shost_gendev.parent = dev ? dev : &platform_bus;
211
212 error = device_add(&shost->shost_gendev);
213 if (error)
214 goto out;
215
Mike Andersond3301872005-06-16 11:12:38 -0700216 scsi_host_set_state(shost, SHOST_RUNNING);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217 get_device(shost->shost_gendev.parent);
218
Tony Jonesee959b02008-02-22 00:13:36 +0100219 error = device_add(&shost->shost_dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220 if (error)
221 goto out_del_gendev;
222
223 get_device(&shost->shost_gendev);
224
James Smart77cca462008-03-21 17:18:23 -0400225 if (shost->transportt->host_size) {
226 shost->shost_data = kzalloc(shost->transportt->host_size,
227 GFP_KERNEL);
228 if (shost->shost_data == NULL) {
229 error = -ENOMEM;
Tony Jonesee959b02008-02-22 00:13:36 +0100230 goto out_del_dev;
James Smart77cca462008-03-21 17:18:23 -0400231 }
232 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233
234 if (shost->transportt->create_work_queue) {
235 snprintf(shost->work_q_name, KOBJ_NAME_LEN, "scsi_wq_%d",
236 shost->host_no);
237 shost->work_q = create_singlethread_workqueue(
238 shost->work_q_name);
James Smart77cca462008-03-21 17:18:23 -0400239 if (!shost->work_q) {
240 error = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700241 goto out_free_shost_data;
James Smart77cca462008-03-21 17:18:23 -0400242 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243 }
244
245 error = scsi_sysfs_add_host(shost);
246 if (error)
247 goto out_destroy_host;
248
249 scsi_proc_host_add(shost);
250 return error;
251
252 out_destroy_host:
253 if (shost->work_q)
254 destroy_workqueue(shost->work_q);
255 out_free_shost_data:
256 kfree(shost->shost_data);
Tony Jonesee959b02008-02-22 00:13:36 +0100257 out_del_dev:
258 device_del(&shost->shost_dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259 out_del_gendev:
260 device_del(&shost->shost_gendev);
261 out:
James Bottomley542bd132008-04-21 10:57:20 -0500262 scsi_destroy_command_freelist(shost);
263 fail:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264 return error;
265}
266EXPORT_SYMBOL(scsi_add_host);
267
268static void scsi_host_dev_release(struct device *dev)
269{
270 struct Scsi_Host *shost = dev_to_shost(dev);
271 struct device *parent = dev->parent;
272
Christoph Hellwigc5478de2005-09-06 14:04:26 +0200273 if (shost->ehandler)
274 kthread_stop(shost->ehandler);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275 if (shost->work_q)
276 destroy_workqueue(shost->work_q);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900277 if (shost->uspace_req_q) {
278 kfree(shost->uspace_req_q->queuedata);
279 scsi_free_queue(shost->uspace_req_q);
280 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282 scsi_destroy_command_freelist(shost);
James Bottomley86e33a22006-08-30 09:45:51 -0400283 if (shost->bqt)
284 blk_free_tags(shost->bqt);
285
Linus Torvalds1da177e2005-04-16 15:20:36 -0700286 kfree(shost->shost_data);
287
Linus Torvalds1da177e2005-04-16 15:20:36 -0700288 if (parent)
289 put_device(parent);
290 kfree(shost);
291}
292
Hannes Reineckeb0ed4332008-03-18 14:32:28 +0100293struct device_type scsi_host_type = {
294 .name = "scsi_host",
295 .release = scsi_host_dev_release,
296};
297
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298/**
299 * scsi_host_alloc - register a scsi host adapter instance.
300 * @sht: pointer to scsi host template
301 * @privsize: extra bytes to allocate for driver
302 *
303 * Note:
304 * Allocate a new Scsi_Host and perform basic initialization.
305 * The host is not published to the scsi midlayer until scsi_add_host
306 * is called.
307 *
308 * Return value:
309 * Pointer to a new Scsi_Host
310 **/
311struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
312{
313 struct Scsi_Host *shost;
Al Viroc53033f2005-10-21 03:22:08 -0400314 gfp_t gfp_mask = GFP_KERNEL;
315 int rval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316
317 if (sht->unchecked_isa_dma && privsize)
318 gfp_mask |= __GFP_DMA;
319
Jes Sorensen24669f752006-01-16 10:31:18 -0500320 shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321 if (!shost)
322 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323
Christoph Hellwig4f777ed2006-11-04 20:11:36 +0100324 shost->host_lock = &shost->default_lock;
325 spin_lock_init(shost->host_lock);
Mike Andersond3301872005-06-16 11:12:38 -0700326 shost->shost_state = SHOST_CREATED;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327 INIT_LIST_HEAD(&shost->__devices);
328 INIT_LIST_HEAD(&shost->__targets);
329 INIT_LIST_HEAD(&shost->eh_cmd_q);
330 INIT_LIST_HEAD(&shost->starved_list);
331 init_waitqueue_head(&shost->host_wait);
332
Arjan van de Ven0b950672006-01-11 13:16:10 +0100333 mutex_init(&shost->scan_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334
335 shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */
336 shost->dma_channel = 0xff;
337
338 /* These three are default values which can be overridden */
339 shost->max_channel = 0;
340 shost->max_id = 8;
341 shost->max_lun = 8;
342
343 /* Give each shost a default transportt */
344 shost->transportt = &blank_transport_template;
345
346 /*
347 * All drivers right now should be able to handle 12 byte
348 * commands. Every so often there are requests for 16 byte
349 * commands, but individual low-level drivers need to certify that
350 * they actually do something sensible with such commands.
351 */
352 shost->max_cmd_len = 12;
353 shost->hostt = sht;
354 shost->this_id = sht->this_id;
355 shost->can_queue = sht->can_queue;
356 shost->sg_tablesize = sht->sg_tablesize;
357 shost->cmd_per_lun = sht->cmd_per_lun;
358 shost->unchecked_isa_dma = sht->unchecked_isa_dma;
359 shost->use_clustering = sht->use_clustering;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700360 shost->ordered_tag = sht->ordered_tag;
361
James Bottomley7a39ac32007-09-25 22:45:53 -0500362 if (sht->supported_mode == MODE_UNKNOWN)
363 /* means we didn't set it ... default to INITIATOR */
364 shost->active_mode = MODE_INITIATOR;
365 else
366 shost->active_mode = sht->supported_mode;
367
Linus Torvalds1da177e2005-04-16 15:20:36 -0700368 if (sht->max_host_blocked)
369 shost->max_host_blocked = sht->max_host_blocked;
370 else
371 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
372
373 /*
374 * If the driver imposes no hard sector transfer limit, start at
375 * machine infinity initially.
376 */
377 if (sht->max_sectors)
378 shost->max_sectors = sht->max_sectors;
379 else
380 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
381
382 /*
383 * assume a 4GB boundary, if not set
384 */
385 if (sht->dma_boundary)
386 shost->dma_boundary = sht->dma_boundary;
387 else
388 shost->dma_boundary = 0xffffffff;
389
Linus Torvalds1da177e2005-04-16 15:20:36 -0700390 device_initialize(&shost->shost_gendev);
391 snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d",
392 shost->host_no);
Hannes Reineckeb0ed4332008-03-18 14:32:28 +0100393#ifndef CONFIG_SYSFS_DEPRECATED
394 shost->shost_gendev.bus = &scsi_bus_type;
395#endif
396 shost->shost_gendev.type = &scsi_host_type;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700397
Tony Jonesee959b02008-02-22 00:13:36 +0100398 device_initialize(&shost->shost_dev);
399 shost->shost_dev.parent = &shost->shost_gendev;
400 shost->shost_dev.class = &shost_class;
401 snprintf(shost->shost_dev.bus_id, BUS_ID_SIZE, "host%d",
402 shost->host_no);
Hannes Reineckef7120a42008-03-18 14:32:28 +0100403 shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700404
Christoph Hellwigc5478de2005-09-06 14:04:26 +0200405 shost->ehandler = kthread_run(scsi_error_handler, shost,
406 "scsi_eh_%d", shost->host_no);
407 if (IS_ERR(shost->ehandler)) {
408 rval = PTR_ERR(shost->ehandler);
James Bottomley542bd132008-04-21 10:57:20 -0500409 goto fail_kfree;
Christoph Hellwigc5478de2005-09-06 14:04:26 +0200410 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700411
412 scsi_proc_hostdir_add(shost->hostt);
413 return shost;
414
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415 fail_kfree:
416 kfree(shost);
417 return NULL;
418}
419EXPORT_SYMBOL(scsi_host_alloc);
420
421struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
422{
423 struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
424
425 if (!sht->detect) {
426 printk(KERN_WARNING "scsi_register() called on new-style "
427 "template for driver %s\n", sht->name);
428 dump_stack();
429 }
430
431 if (shost)
432 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
433 return shost;
434}
435EXPORT_SYMBOL(scsi_register);
436
437void scsi_unregister(struct Scsi_Host *shost)
438{
439 list_del(&shost->sht_legacy_list);
440 scsi_host_put(shost);
441}
442EXPORT_SYMBOL(scsi_unregister);
443
Tony Jonesee959b02008-02-22 00:13:36 +0100444static int __scsi_host_match(struct device *dev, void *data)
Dave Young9c770102008-01-22 14:01:34 +0800445{
446 struct Scsi_Host *p;
447 unsigned short *hostnum = (unsigned short *)data;
448
Tony Jonesee959b02008-02-22 00:13:36 +0100449 p = class_to_shost(dev);
Dave Young9c770102008-01-22 14:01:34 +0800450 return p->host_no == *hostnum;
451}
452
Linus Torvalds1da177e2005-04-16 15:20:36 -0700453/**
454 * scsi_host_lookup - get a reference to a Scsi_Host by host no
Linus Torvalds1da177e2005-04-16 15:20:36 -0700455 * @hostnum: host number to locate
456 *
457 * Return value:
458 * A pointer to located Scsi_Host or NULL.
459 **/
460struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
461{
Tony Jonesee959b02008-02-22 00:13:36 +0100462 struct device *cdev;
Dave Young9c770102008-01-22 14:01:34 +0800463 struct Scsi_Host *shost = ERR_PTR(-ENXIO);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464
Tony Jonesee959b02008-02-22 00:13:36 +0100465 cdev = class_find_device(&shost_class, &hostnum, __scsi_host_match);
Dave Young9c770102008-01-22 14:01:34 +0800466 if (cdev)
467 shost = scsi_host_get(class_to_shost(cdev));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700468
469 return shost;
470}
471EXPORT_SYMBOL(scsi_host_lookup);
472
473/**
474 * scsi_host_get - inc a Scsi_Host ref count
475 * @shost: Pointer to Scsi_Host to inc.
476 **/
477struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
478{
Mike Andersond3301872005-06-16 11:12:38 -0700479 if ((shost->shost_state == SHOST_DEL) ||
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480 !get_device(&shost->shost_gendev))
481 return NULL;
482 return shost;
483}
484EXPORT_SYMBOL(scsi_host_get);
485
486/**
487 * scsi_host_put - dec a Scsi_Host ref count
488 * @shost: Pointer to Scsi_Host to dec.
489 **/
490void scsi_host_put(struct Scsi_Host *shost)
491{
492 put_device(&shost->shost_gendev);
493}
494EXPORT_SYMBOL(scsi_host_put);
495
496int scsi_init_hosts(void)
497{
498 return class_register(&shost_class);
499}
500
501void scsi_exit_hosts(void)
502{
503 class_unregister(&shost_class);
504}
505
506int scsi_is_host_device(const struct device *dev)
507{
Hannes Reineckeb0ed4332008-03-18 14:32:28 +0100508 return dev->type == &scsi_host_type;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700509}
510EXPORT_SYMBOL(scsi_is_host_device);
511
512/**
513 * scsi_queue_work - Queue work to the Scsi_Host workqueue.
514 * @shost: Pointer to Scsi_Host.
515 * @work: Work to queue for execution.
516 *
517 * Return value:
Michael Reeddd7e2f22006-08-04 12:09:24 -0500518 * 1 - work queued for execution
519 * 0 - work is already queued
520 * -EINVAL - work queue doesn't exist
Linus Torvalds1da177e2005-04-16 15:20:36 -0700521 **/
522int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
523{
524 if (unlikely(!shost->work_q)) {
525 printk(KERN_ERR
526 "ERROR: Scsi host '%s' attempted to queue scsi-work, "
527 "when no workqueue created.\n", shost->hostt->name);
528 dump_stack();
529
530 return -EINVAL;
531 }
532
533 return queue_work(shost->work_q, work);
534}
535EXPORT_SYMBOL_GPL(scsi_queue_work);
536
537/**
538 * scsi_flush_work - Flush a Scsi_Host's workqueue.
539 * @shost: Pointer to Scsi_Host.
540 **/
541void scsi_flush_work(struct Scsi_Host *shost)
542{
543 if (!shost->work_q) {
544 printk(KERN_ERR
545 "ERROR: Scsi host '%s' attempted to flush scsi-work, "
546 "when no workqueue created.\n", shost->hostt->name);
547 dump_stack();
548 return;
549 }
550
551 flush_workqueue(shost->work_q);
552}
553EXPORT_SYMBOL_GPL(scsi_flush_work);